California Billionaire Tax Faces Constitutional Fight

According to Financial Advisor Magazine, a new Tax Foundation analysis warns that California's Proposition 40, a proposed one-time 5% wealth tax on billionaires, could be invalidated by courts before generating any revenue. The analysis by Jared Walczak cites constitutional vulnerabilities around retroactivity, property taxation, and the right to travel, and argues the tax would likely be treated as a property tax, not the excise tax its language claims. Walczak says California might lose wealthy residents, face years of litigation, and collect nothing if the measure is struck down.

Family offices and UHNW clients with California exposure face significant planning uncertainty. If Prop 40 survives court review, qualifying residents would owe a one-time 5% levy on net worth as of Dec. 31; if it falls, the threat may still trigger relocation decisions. Advisors should watch the November ballot and any preliminary rulings.